Extending the time interval for applying herbicide in cut-stump treatments on American beech

Abstract

American Beech (Fagus grandifolia Ehrh.) root sprouts often form dense understories that interfere with tree reproduction throughout much of the eastern hardwood region. The cut-stump treatment, whereby herbicide is applied to the stump within a few hours after a larger beech is felled, has been shown to mitigate the interference problem by eliminating beech stems attached to the parent tree's root system. Forest managers are often reluctant to prescribe this treatment because the short time interval between felling the tree and applying herbicide requires the applicator to work in proximity to an active logging operation, raising concerns about safety and efficiency. This study measured the efficacy of the cut-stump treatment on American beech root and stump sprouts for eight time intervals, ranging from 1 to 120 hours, on a 60-acre study site in central West Virginia. Glyphosate as Razor Pro herbicide was diluted to a 65.6% solution with water (26.9% active ingredient) and applied to the outer 2 in. of beech stumps from trees 11-15 in. dbh. The treatments were applied during a cool humid period in September and evaluated 12 months later. Control of root sprouts ranged from 71 to 86%, with no significant differences among the 1- to 96-hour treatments. Efficacy dropped to 50% and 1% for the 120-hour treatment and control treatment, respectively. Stump sprouts were prevented on all stumps treated within 96 hours of tree severing. The results indicated that herbicide can be applied to beech stumps up to four days after severing without reducing control of root and stump sprouts under the conditions in this study. The longer time interval will improve feasibility, safety, and efficiency of the cut-stump treatment. In practice, the effective time interval may vary depending on season of the year and weather conditions.